This morning I stopped at the parts store and grabbed a can of engine brite. Went to the local "diy" car wash w/ a pressure washer, opened the hood and sprayed the engine brite all over the hot engine. Not what you're supposed to do, but ahh well. I let it sit for a few minitues then pumped some change into the machine. Turned it to rinse and hosed down the engine. I didnt use the high pressure trigger, I just let it spray on low pressure (which is still relatively forceful for this purpose). I made short and quick passes over items such as the air box, distributor, valve cover, fuse box etc. After rinsing the entire bay, I started the car and let it run for 10 mins or so. Not one peep, miss, stumble or service light experienced, so I drove away. The end. I'm not saying you dont have to cover anything, or you shouldnt cover anything, Im just saying that I didnt and I had no problems...